We are investigating the mechanisms whereby steroid and polypeptide hormones stimulate growth and specific protein synthesis in human breast cancer both in tissue culture model systems we have established and in clinical settings. A. We are studying the prevalency and clinical correlates of specific steroid receptors for estrogen, androgen, glucocorticoid and progesterone in human breast cancer, lymphomatous diseases, melanoma, colon carcinoma, ovarian cancer and male breast cancer. B. Assays for specific gene products (-lactalbumin, casein, fatty acid synthetase, thymidine kinase) Thymidylate synthetase, aspartate transcarbamylase dihydrofolate reductase have been developed and we are studying the effects of steroid hormones on the activities and synthesis of these proteins.